Fix several clazy issue:

* Use multi-arg instead [-Wclazy-qstring-arg]
* Use an empty QLatin1String instead of an empty QStringLiteral [-Wclazy-empty-qstringliteral]
* getter Gui::ProgressBar::canAbort possibly mismarked as a slot [-Wclazy-const-signal-or-slot]
* Missing emit keyword on signal call [-Wclazy-incorrect-emit]

src/Gui/QuantitySpinBox.cpp

@@ -601,7 +601,7 @@ void QuantitySpinBox::updateFromCache(bool notify, bool updateUnit /* = true */)
             d->pendingEmit = false;
             Q_EMIT valueChanged(res);
             Q_EMIT valueChanged(res.getValue());
-            textChanged(text);
+            Q_EMIT textChanged(text);
         }
     }
 }